Intensely roasted from hulless barley, Blackprinz® Malt is an amazingly smooth and mellow flavored black malt without bitter, astringent, dry flavors or aftertaste. Despite its delicate and clean flavor Blackprinz® Malt won’t disappoint the eye, delivering exceptionally deep color to dark beers or a slight to intense boost of color to other beer styles. The hints of toasted malty flavor that come through at slightly higher usage rates make Blackprinz® Malt a unique member and truly the crown jewel of the black malt category.

Im making a stout and decide to use this instead of Roasted Barley. Is this a reasonable substitution? How much would be appropriate to use in a 5gl batch?

Not familiar with that malt either but it sounds like a substitute for black patent. Use in very small quantities for color. Roasted barley does add flavor and you will be lacking that roasted coffee flavor if you substitute this. Absolutely crush all grains.